Porcine Small and Large Intestinal Microbiota Rapidly Hydrolyze the Masked Mycotoxin Deoxynivalenol-3-Glucoside and Release Deoxynivalenol in Spiked Batch Cultures In Vitro

Abstract

Mycotoxin contamination of cereal grains causes well-recognized toxicities in animals and humans, but the fate of plant-bound masked mycotoxins in the gut is less well understood. Masked mycotoxins have been found to be stable under conditions prevailing in the small intestine but are rapidly hydrolyzed by fecal microbiota. This study aims to assess the hydrolysis of the masked mycotoxin deoxynivalenol-3-glucoside (DON3Glc) by the microbiota of different regions of the porcine intestinal tract. Intestinal digesta samples were collected from the jejunum, ileum, cecum, colon, and feces of 5 pigs and immediately frozen under anaerobic conditions. Sample slurries were prepared in M2 culture medium, spiked with DON3Glc or free deoxynivalenol (DON; 2 nmol/ml), and incubated anaerobically for up to 72 h. Mycotoxin concentrations were determined using liquid chromatography-tandem mass spectrometry, and the microbiota composition was determined using a quantitative PCR methodology. The jejunal microbiota hydrolyzed DON3Glc very slowly, while samples from the ileum, cecum, colon, and feces rapidly and efficiently hydrolyzed DON3Glc. No further metabolism of DON was observed in any sample. The microbial load and microbiota composition in the ileum were significantly different from those in the distal intestinal regions, whereas those in the cecum, colon and feces did not differ. Results from this study clearly demonstrate that the masked mycotoxin DON3Glc is hydrolyzed efficiently in the distal small intestine and large intestine of pigs. Once DON is released, toxicity and absorption in the distal intestinal tract likely occur This study further supports the need to include masked metabolites in mycotoxin risk assessments and regulatory actions for feed and food.

Modified Fusarium Mycotoxins in Cereals and Their Products—Metabolism, Occurrence, and Toxicity: An Updated Review

“…In addition, the rapid hydrolysis of DON-3Glc to DON was observed in the faeces of one of the participants (up to 2 h incubation); this was followed by the presence of DOM-1 observed after incubation for 6 h. The presence of DOM-1 was not identified in material from other volunteers, even after seven days of incubation [ 149 ]. Similar results were reported by Gratz et al [ 150 ], who studied hydrolysis of DON-3Glc in pig intestines. Samples of digested byproducts collected post-mortem from jejunum, ileum, cecum, colon, and faeces were incubated for 72 h with DON-3Glc or free DON in anaerobic conditions.…”

“…Small intestine microflora hydrolysed DON-3Glc very slowly, while samples from ileum, cecum, colon, and faeces were hydrolysed quickly and efficiently. No further metabolism of DON was observed in any of the samples even if composition of microflora residing in ileum was quite different than composition of microflora in the distal gut, while composition of microflora in cecum, colon, and faeces did not differ [ 150 ].…”

Fumonisin-Exposure Impairs Age-Related Ecological Succession of Bacterial Species in Weaned Pig Gut Microbiota

“…Studies on mycotoxin actions on gut microbiota are rare [ 11 , 13 ] and they mainly concern the effect of deoxynivalenol [ 12 , 28 , 29 , 30 ] and aflatoxins [ 31 , 32 ]. After two weeks of dietary exposure to FB1, the diversity of the fecal bacterial community decreases.…”

Prevalent Human Gut Bacteria Hydrolyse and Metabolise Important Food-Derived Mycotoxins and Masked Mycotoxins

“…Then, 4 µL of bacterial culture (in triplicate for each strain) were inoculated into 196 µL of medium (as specified in Section 4.2 ) containing either DON, DOM-1, DON-Glc, T-2, HT-2, or HT-2-Glc in acetonitrile (at 2 or 10 nmol/mL). The mycotoxin concentration of 2 nmol/mL was used to assess the hydrolysis/metabolism of masked or unconjugated mycotoxins by human gut bacteria in accordance with published studies [ 9 , 12 ]. The effect of mycotoxins on bacterial growth was assessed at 2 and 10 nmol/mL.…”

“…Over the last decade several studies have assessed the fate of DON-Glc and other masked mycotoxins under gastrointestinal conditions in vitro and in vivo, and most studies have found masked mycotoxins to be stable towards small intestinal digestion and not to be absorbed intact [ 5 ]. However, microbial hydrolysis of masked mycotoxins by human gut microbiota is well described in vitro [ 6 , 7 , 8 , 9 , 10 ] and further confirmed in pig microbiota [ 11 , 12 ]. Furthermore, the release of DON from a dose of DON-Glc and subsequent absorption and urinary excretion have recently been confirmed to occur in vivo in humans [ 13 ].…”